It is known to use magnetorheological finishing (MRF) uses magnetorheological (MR) fluid to polish or remove materials from surfaces of optical lens. The MR fluids include suspensions of ferro-magnetic particles carried by a carrier fluid. Under influence of a magnetic field, the ferro-magnetic particles are magnetized by the magnetic field and viscosity of the MR fluid changes almost instantaneously from a liquid state to a semi-solid state which is still sufficiently pliant to conform to a surface of a workpiece being polished. However, for certain applications, such as removal of sub-surface damage including sub-surface micro-crack, current MRF techniques do not yield sufficiently useful material removal rates for required production yields. Commercially available glass polishing disks are also not suitable for removing sub-surface micro-cracks.
There is therefore a need to provide an apparatus and method for polishing an edge of an article using magnetorheological fluid to address at least one of the disadvantages of the prior art and/or to provide the public with a useful choice.